1. Technical Field
Disclosed herein is a shift logic for a ground ripping machine that enables the controller of the machine to shift the machine from an auto-shift mode, where the operator selects a desired gear or speed, to an auto-ripping mode, which requires a downshift to a low or first gear and operation at a high throttle setting, and vice versa.
2. Description of the Related Art
Mobile excavation machines, such as dozers, agricultural tractors, and scrapers, often include one or more ripping tools for cultivating, digging, ripping or otherwise disturbing a ground surface. The ground surface may include non-homogenous loose soil or compacted material that can be easy or difficult for the machine to process. As the machines traverse a site that has changing terrain and/or varying ground surface conditions, the magnitude of resistance applied to the ripping tool can vary greatly. In order to ensure that a maximum productivity of the machine is achieved without damaging the machine, the operator of the machine must continuously alter settings of the machine and the ripping tool to accommodate the changing terrain and ground surface conditions. This continuous altering can be tiring for even a skilled operator and difficult, if not impossible, for a novice operator to achieve optimally.
One way to efficiently accommodate changes in terrain and surface composition may include automatically controlling the machine during portions of the excavation process. An automatically controlled machine is disclosed in US2012267128. This published application discloses an automated control of the ripping tool wherein, if one or more criteria are met that indicate the ripping operation has ended, the ripping tool is automatically pulled upward and tilted to a default position. The automated return of the ripping tool to the default position saves the operator from operating two different levers used to position the ripping tool while contemporaneously steering and operating other components of the machine.
Some machines may be equipped with automatic ripping control mode (“auto-ripping mode”), which is a feature that automates the raising and lowering of the ripping tool and adjusts the throttle to optimize the ripping operation. Normally, auto-ripping modes require the transmission of the machine to be in a low or first gear and the throttle is set to a high setting or full throttle. Another feature offered on some machines is an automatic shift mode (“auto-shift mode”), which is a shift control algorithm that allows the operator to select a desired machine speed, which may be a maximum allowable transmission output speed for the machine. In auto-shift mode, the controller may be programmed to automatically adjust the throttle and transmission gear to achieve an appropriate transmission output speed for the current load on the machine that is less than or equal to the desired machine speed.
Although such automated control systems may improve machine efficiency and reduce operator fatigue by automating some of the functions normally controlled by the operator, the benefits are limited because it is difficult to change the operation of the machine from an auto-ripping mode to an auto-shift mode and vice versa. Specifically, to go from an auto-shift mode to an auto-ripping mode, the transmission must be shifted to a low or first gear and the throttle increased to full throttle or near full throttle. Conversely, to go from an auto-ripping mode to an auto-shift mode, the operator must enter a desired speed, the throttle must be reduced and the transmission shifted to the appropriate gear based on the speed entered by the operator and the load imposed on the machine. Further, the operator must re-enter the desired speed every time the machine is shifted from an auto-ripping mode to an auto-shift mode.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above.